I've also used Apple - conditioner and rain-n-stain guard - on all my Kristins and they look great! I don't have any metallic Kristins, just the regular leather. I pretty much ignore the Coach care cards, a lot of them say don't treat with anything, I use Apple anyway.
+1
just make sure to do a spot test first and leave for 24hrs, if it all looks good then go ahead and treat the whole item.